The use of neuromuscular incapacitation (NMI) devices (and other stun devices that emit electrical discharges against a target mammal) has increased over the last decade to encompass over 200,000 units in operation worldwide with over 800,000 actual firing deployments involving training personnel and law enforcement incidents. The output of stun devices is electrical in nature and thus may not leave an identifying mark or clear trace of historical events, unlike a bullet, that normally leaves such a mark. Furthermore, stun devices are designed to incapacitate effectively and temporarily an individual based on a unique and specific electrical output, as stated by a manufacturer.
Currently, there are many stun devices available around the world, featuring a variety of outputs with respect to voltage, current, waveform, and timing intervals. While many are available, however, only a limited number of manufacturers sell stun devices in a gun form-factor. U.S. Pat. Nos. 7,234,262 and 6,636,412 by Taser International and U.S. Pat. No. 6,575,073 by Stinger Systems all describe currently available commercial stun devices. The disclosures of these patents are hereby incorporated by reference herein in their entireties. The electrical output of each company's device differs significantly from the others and within each specified output for a given load, but each manufacturer makes their own claims of effectiveness and safety, as discussed below. The differences and characteristics of electrical output of stun devices are known from detailed and sophisticated measurements with a variety of specialized oscilloscopes and related measuring tools.
FIGS. 1 and 2 and TABLE 1 show detailed traces of waveforms under specific conditions using sophisticated oscilloscopes as well as a summary of typical electrical output for a variety of related, electrically-focused technologies used in the medical profession and other fields. FIG. 1 shows waveforms from a commercially available stun device of a hand-held type, illustrating several important features of the waveform, including pulse height and charge, repetition rate, slope of the peak, duration of the waveform, changing shape of the waveform and total energy delivered. FIG. 2 shows additional details of an “idealized” waveform discharged by a device presently in commercial use, indicating a variety of characteristics. The characteristics shown in FIGS. 1 and 2 define the waveform of choice for a given device and manufacturer. TABLE 1 provides a comparison of stun devices, and includes similar information for biomedical devices employing electrical current, such as Electroconvulsive (ECT) therapy, cauterizing devices (electro-surgery), and defibrillators.
TABLE 1Electrical Discharge Comparison of Various Device TypesVoltageCurrentPulse DurationPulse FrequencyPowerElectric Fencing5-10kV10-20mA0.1-1sec0.5-1Hz0.1-18J/pulseEarly Stun Devices40-100kV3-4mA~20μsec5-20Hz0.8J/pulse7 watt TaserCurrent Stun Devices18-50kV2-4 mA average 11μsec10-25Hz0.1-1.8J/pulse26 watt Taser18 A peakECS, ECT70-450V20-900mA1.5msec70Hz0.6J/pulseDefibrillators~750-1500V20-65A5-7msec1-6total100-360J/pulseElectrosurgery1000-9000Vvariablevariable<200,000Hz80-300Watts
It is helpful to note that a manufacturer's claim of effectiveness and safety must be linked directly to a consistent electrical output. Manufacturers have conducted various safety studies involving humans and animals to allay public fears and to use as a defense in litigation, where the actual output of the device is considered to have been a cause of injury or death of the target. Thus, lacking regulatory approval of a universal waveform, each company documents its waveform's safety by performing safety studies for its own devices. While safety factors of each waveform have been disclosed in publications, the device use data and associated instances of injury and death to date also reveals significant questions regarding safety. Thus, the identity and integrity of a specific waveform is of high value to a number of stakeholders including manufacturers, end-users (e.g., law enforcement) and the public on whom the devices are deployed for non-lethal purposes. Examples of studies resulting in claims of both safety and potential injury can be found, for example, in the following publications: Jeffrey D. Ho, MD, James R. Miner, MD, Dhanunjaya R. Lakireddy, MD, Laura L. Bultman, MD, William G. Heegaard, MD, MPH, “Cardiovascular and Physiologic Effects of Conducted Electrical Weapon Discharge in Resting Adults,” ACADEMIC EMERGENCY MEDICINE, 13:589-595 (2006); Valentino, D. J., Walter, R. J., Dennis, A. J., Nagy, K., Loor, M. M., & Winners, J. et al., “Neuromuscular effects of stun device discharges,” JOURNAL OF SURGICAL RESEARCH, 143(1), 78-87 (2007); Valentino, D. J., Walter, R. J., Nagy, K., Dennis, A. J., Winners, J., & Bokhari, F. et al., “Repeated thoracic discharges from a stun device,” JOURNAL OF TRAUMA—INJURY, INFECTION AND CRITICAL CARE, 62(5), 1134-1142 (2007); A. Esquivel, E. Dawe, J. Sala-Mercado, R. Hammond, C. Bir, “The Physiologic Effects of a Conducted Electrical Weapon in Swine,” ANNALS OF EMERGENCY MEDICINE, Vol. 50, Issue 5, Pages 576-583 (2007); Lakkireddy, D., Khasnis, A., Antenacci, J., Ryshcon, K., Chung, M. K., & Wallick, D. et al., “Do electrical stun guns (TASER-X26®) affect the functional integrity of implantable pacemakers and defibrillators?,” EUROPACE, 9(7), 551-556 (2007); and Lakkireddy, D., Wallick, D., Ryschon, K., Chung, M. K., Butany, J., & Martin, D. et al., “Effects of cocaine intoxication on the threshold for stun gun induction of ventricular fibrillation,” JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, 48(4), 805-811 (2006). The disclosures of these references are hereby incorporated by reference herein in their entireties.
Notwithstanding a manufacturer's claim of safety, electric stun device safety can only be assured if the stated waveform is both proven safe and is consistently produced and delivered by the device. Given the importance of this link between device output, safety, and effectiveness, we have determined it to be desirable that the output be verifiable for a given device during its cycle of normal duty and on a schedule of appropriate timing to ensure that only devices having outputs that are studied and verified safe are used on targets. However, there is no easy, simple way to verify device output on a regular basis within the typical law enforcement context. Thus, we have determined that verification of device output is needed in the law enforcement setting, in a testing apparatus that is simple to operate and inexpensive to purchase.
It also is reasonable to assume that as stun devices of different manufacturers and types become even more widely deployed and better studied, there will be a need to examine in detail the output of a specific device or class of devices. This output may be in relation to a specific incident or a class of incidents in which one or more devices are involved, including devices by different manufacturers. In such a case, currently, it is necessary to use sophisticated oscilloscopes operated by an expert or someone very familiar with the measurement equipment and the particular features of stun devices to capture, study and analyze the device's electrical output. Further, the waveform must be interpreted to assess whether it is, in fact, safe. While this approach may be helpful in determining the safety of a device right off the assembly line, stun devices are rarely, if ever, tested after being in the field for a period of time. Moreover, any tests performed on a particular device are often performed only after a discharge against a target has occurred, usually, and unfortunately, after there exists a reason for testing (e.g., an unintentional death of a target during deployment). There is essentially no focus on the actual routine verification of output prior to routine use. In addition, because electrical currents are transient and may not leave tangible traces that are currently recognized by the medical profession, the commonly recognized characteristics of an electrical discharge (voltage, amplitude, etc.) are often the only measure of output that was received by the target. These commonly recognized characteristics may not be sufficient, in all circumstances, to determine adequately or reliably the reason for an adverse result (i.e., a death of a target).
Moreover, if one follows the analogy of forensic study of ballistic evidence, it is clear that the capability to collect and analyze electric stun discharge evidence is lacking Thus, we have determined that it is highly advantageous to have a device or series of measurement devices that are easy to operate and interpret and are linked to the known waveform output of stun devices available. While some attempts are being made to develop systems to test particular stun devices from a specific manufacturer, these attempts do not appear to contemplate a device that test both existing and not-yet-developed stun devices, or to test and compile information on both existing and not-yet-developed stun devices to enable research into the safety and efficacy of electric waveforms and stun devices, generally. See, e.g., Nelson Bennett, “Tasers' test results sparks invention,” Richmond News (Sep. 9, 2009) (available at http://www2.canada.com/richmondnews/news/story.html?id=0fa3b787-b632-4543-a991-354de3f9cd74), the disclosure of which is hereby incorporated by reference herein in its entirety. Additionally, having these devices readily available (both economically and physically) would allow law enforcement departments and forensic investigators and coroners the capability of in-depth analysis of stun device discharges, as needed.
Stun device output is a function, in part, of the internal electronic circuitry designed to produce a given waveform of a given magnitude and duration. We have determined that it would be desirable for the discharge output to be verified during the life cycle of a device. Changes in output can occur due to a number of factors, including, but not limited to, defective manufacture, component failure due to use, current leakage to operator, change in manufacturing components, deliberate alteration of components and power supply, etc. Additionally, manufacturers develop and sell successor models of stun devices (e.g., Taser models M18, M26, X26, wireless systems, sentry systems; see www.taser.com) and may alter the original waveform and output as models change over time. Moreover, nearly all projectile-based gun-platform stun devices may also deliver a subcutaneous electrical discharge significantly different than a discharge directly against the skin. Thus, manufacturers' stated claims of output should not be relied upon as accurate over the lifetime of use of the device, nor across successor models. It would be desirable to verify such output on a routine basis.
Currently, stun device output is not regulated at the state or federal level with respect to waveform or magnitude, nor are manufacturing standards tied to any stated degree of device performance or acceptable deviation from stated specifications. Without verification, there is little, if any, accountability for holding manufacturers responsible for quality performance features. The lack of verification is problematic for law enforcement officials who use the devices routinely and who may be involved in litigation due to a specific, often fatal, incident. Such details become important in complex deployment situations where drugs, alcohol and extreme agitation, as well as a victim's pre-existing conditions (such as use of pacemakers, etc.) are present. Medical experience has shown that risks from electrical stimulation include abnormal heart rhythms, epileptic seizures, cell injury and death. While there is an extensive history of the use of stun-devices with no apparent long term effects, the possibility exists. Variations from the normal stimuli are of particular concern. For example very fast, high-amplitude transients can produce injury inside of cells. Ventricular fibrillation can be induced more easily at some rates, as well. Thus, a convenient and cost effective program by law enforcement to track and record the features of the devices deployed over time may be desirable.
Currently, a number of oscilloscopes and other measuring devices are employed for the detailed analysis of waveforms and output of stun devices. Many of these measuring devices and oscilloscopes are sophisticated with respect to data capture rate, range and magnitude of signal, signal sampling parameters, and ability to analyze, record and handle large amounts of stored data. The technology involved in typical electrical output analysis includes a multimeter as described in U.S. Pat. No. 7,342,393, issued Mar. 11, 2008, to Newcombe; combination test instruments and voltage detectors as described in U.S. Pat. No. 7,242,173, issued Jul. 10, 2007, to Cavoretto; devices generating electronic test signals as described in U.S. Pat. No. 6,944,569, issued Sep. 13, 2005, to Harbord; digital oscilloscopes with waveform pattern recognition as described in U.S. Pat. No. 6,621,913, issued Sep. 16, 2003, to de Vries; specialized circuits for measuring in-circuit resistance and current as described in U.S. Pat. No. 5,804,979, issued Sep. 8, 1998, to Lund; and devices designed to detect minimum pulse widths of waveforms as described in U.S. Pat. No. 5,708,375, issued Jan. 13, 1998, to Lemmens. U.S. Pat. No. 6,469,492, issued Oct. 22, 2002, to Britz and U.S. Pat. No. 5,930,745, issued Jul. 27, 1999, to Swift disclose additional testing equipment. The disclosures of each of the above-identified references are incorporated by reference herein in their entireties.
Additionally, there are a number of devices that are used to measure and verify electrical signals from a variety of biomedical devices including defibrillators, as described in U.S. Published Patent Application No. 2007/0226574, published Sep. 27, 2007, by Ryan; pacemakers, as described in U.S. Pat. No. 5,209,228, issued May 11, 1993, to Cano; electro-surgery devices; and others. Many electrical testing devices provide comparisons with known electrical standards such as the International Electrotechnical Commission (IEC) and the Association for the Advancement of Medical Instrumentation (AAMI). The disclosures of each of the above-identified references are incorporated by reference herein in their entireties.
However, no universal test devices currently exist that can meet the needs described above for known and to-be-developed stun devices. Additionally, there presently exists no method for imposing accountability on users or manufacturers of stun devices by proving how a particular stun device was operating prior to discharge during routine use against a target. Moreover, there exists no system for collecting information about stun device discharge characteristics to study the effects of stun devices on an industry-wide basis.